[Help] Convert integer to Roman numerals? {Screenshot attached}

[vanicci]

[Help] Convert integer to Roman numerals? {Screenshot attached}

Hi,

Please see attached screenshot for the current exercise that I'm trying to execute?

[Image: 060818_zps7cdg6nrb.png]

Tbh, I am also unsure with my code. I gathered the idea from here (https://stackoverflow.com/questions/2877...n-numerals)

===================================================================
Here's my currentcode:

print("[System] Hi! Enter any number between 1 and 3000 so the program will show you the old-school Roman numeral. In other words, 4 should return 'IIII'. Ready?!")

num_map = [(1000, 'M'), (500, 'D'), (100, 'C'), (50, 'L'), (10, 'X'), (5, 'V'), (1, 'I')]
num = int(input("Enter any number between 1 and 3000: "))

def num2roman(num):

    while num > 0:
        for key, val in num_map:
            while num >= 1:
                print(num_map.values())
num2roman(num)

===================================================================
Error:

Error:
Traceback (most recent call last):
  File "soc-wk1day4h-cert-vanessa-dunford.py", line 25, in <module>
    num2roman(num)
  File "soc-wk1day4h-cert-vanessa-dunford.py", line 24, in num2roman
    print(num_map.values())
AttributeError: 'list' object has no attribute 'values'

===================================================================

Any advice is much appreciated! :)

Thank you in advance!

[volcano63]

For starters, you need a dict - not list of tuples

num_map = {1000: 'M', 500: 'D', 100: 'C', 50: 'L', 10: 'X', 5: 'V', 1: 'I'}

[Windspar]

List of tuples are fine. Just need to expand it.

roman_map = [(1000, "M"), (900, "CM"), (500, "D"), (400, "CD"), (100, "C"),
    (90, "XC"), (50, "L"), (40, "XL"), (10, "X"), (9, "IX"), (5, "V"),
    (4, "IV"), (1, "I")]

Only have 1 loop.

def num2roman(num):
    while num > 0:

keep track of roman numeral

def num2roman(num):
    numeral = ""
    while num > 0:

keep track where at in list.

def num2roman(num):
    numeral = ""
    pos = 0
    while num > 0:

in loop use if block to see if num > then value and - value from num. Else increase pos.

[volcano63]

List of tuples are fine. Just need to expand it.

I don't know what they thought when they created dict in Python .

Really bright idea - propose un-Pythonic complicated mapping instead of standard dictionary

[ichabod801]

The tuples are better than a dict. You need to subtract the numbers in order, and the list of tuples provides the order. I think it would be more pythonic to loop through the tuples rather than keep track of an index, but a dictionary is not the proper tool here.

[Windspar]

@volcano63
Walking through a list of tuples seem pretty elegant.
Since it not jumping around the list.

Saying something is un-Pythonic. Doesn't make it so.

---

Changing list to a tuple probably be better. Just because it keeps it all immutable.

roman_map = ((1000, "M"), (900, "CM"), (500, "D"), (400, "CD"), (100, "C"),
    (90, "XC"), (50, "L"), (40, "XL"), (10, "X"), (9, "IX"), (5, "V"),
    (4, "IV"), (1, "I"))

But not a must.

[vanicci]

@volcano63 & @ichabod801 = Thank you very much for your input! :)

@Windspar, can I please ask you to look into my current code?

When user input's integer, there is no roman numeral coming up?

print("[System] Hi! Enter any number between 1 and 3000 so the program will show you the old-school Roman numeral. In other words, 4 should return 'IIII'. Ready?!")

num_map = [(1000, 'M'), (900, 'CM'), (500, 'D'), (400, 'CD'), (100, 'C'), (90, 'XC'),
           (50, 'L'), (40, 'XL'), (10, 'X'), (9, 'IX'), (5, 'V'), (4, 'IV'), (1, 'I')]

result = int(input("Enter any number between 1 and 3000: "))
num = 0

def int_to_roman(num):
    result = []
    for (arabic, roman) in num_map:
        (factor, num) = divmod(num, arabic)
        result.append(roman * factor)
        if num == 0:
            break
    return "".join(result)

int_to_roman(num)

===================================================================
My Terminal's Screenshot:

[Image: 060818_zpsmx8wa1rw.png]

[ichabod801]

You need to print the result for it to show up on the screen. Change your last line to:

print(int_to_roman(num))

[Windspar]

Try

print(int_to_roman(int(result)))

[ichabod801]

She's covering using the same numeral multiple times with the divmod. Note to OP: that integer division (//) will give you the integer portion without the remainder, which you aren't using.